Djibouti on Friday accused Eritrean soldiersof occupying territory in the contested Doumeira region following the departure of Qatari peacekeepers from the location earlier this week.

Doumeira is situated northeast of Djibouti and east of Eritrea near the Bab el-Mandeb strait, a strategic waterway at the foot of the Red Sea through which nearly four million barrels of oil are shipped daily to Europe, the United States and Asia.

Moussa Faki Mahamat, AU commission chairperson, said on Saturday that the union would send a "fact-finding mission to the Djibouti-Eritrea border".

The AU is "ready to assist Djibouti and Eritrea to normalise their relations and promote good neighbourliness within the framework of relevant AU instruments," he said.

Qatar announced that it was pulling its contingent out on June 14, days after the two East African countries sided with Saudi Arabia, the United Arab Emirates and their allies in a major diplomatic standoff with Doha.

Qatar's foreign ministry did not give a reason for the move.

Djibouti's Foreign Minister Mahamoud Ali Youssef said on Friday that his country's army was "on alert" and accused Eritrea of "moving its forces" into the Doumeira region where Qatari peacekeepers had been stationed since 2010 as a buffer between the two nations' armies.